Fitting for perforating steel walled members



July 4, 1961 P. D. MERRILL ETAL 2,990,731

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HTTOENEK United States Patent Ind! Filed June 29, 1959, Ser. No. 823,595 'Claims. (Cl. 77-37) This invention relates to a fitting for perforating steel walled members, such as pipes and fluid containers, and is particularly well suited for use as a branch pipe fitting. The fitting is of the type and constitutes an improvement upon the fitting forming the subject matter of a patent application of Patterson D. Merrill and Harry T. Waite, Jr., for Fitting for Tapping Steel WalledMembers, Serial No. 776,095, filed November 24, 1958 which issued as Patent No. 2,950,637, dated August 30, 1960'.

The primary object of this invention is to provide a device of this character which is self-contained, in that perforating means forms a part thereof and is retained therein for dual use as a valve member to control the flow of fluid contents through the device and the perforation formed thereby.

A further object is to provide a device of this character which forms a perforation by removing a portion of a wall in the form ,of a slug in such a manner as to insure that the slug is completely separated from the wall in which it is formed and is prevented from hinging to said wall at the margin of the perforation.

A further object is to provide a device of this character having a novel perforating member capable of displacing metal in the form of a slug in a perforating operation, which metal displacement occurs with some of the characteristics of a metal extrusion.

A further object is to provide a device of this character having an elongated perforating member screw-threaded at the end thereof remote from the perforating end, and means for guiding said member with minimum friction to counteract forces acting on the perforator and tending to distort the same from true axial position during its use.

Other objects will be apparent from the following specification.

Referring to the drawing which illustrates the preferred embodiments of the invention,

FIG. 1 is a longitudinal sectional view of the device used upon a steel pipe and illustrating the same in use to permit flow therethrough from the pipe through the opening perforated thereby;

FIG. 2 is a fragmentary sectional view illustrating the tip of the perforating tool seated in the perforation formed thereby;

FIG. 3 is an enlarged fragmentary detail sectional view illustrating an intermediate step in the process of using the tool to perforate a steel wall;

FIG. 4 is a transverse sectionalview taken on line 4-4 of FIG. 1;

FIG. 5 is a side view of a typical slug formed by the use of the device;

FIG. 6 is an axial sectional view of the slug shown in FIG. 5;

FIG. 7 is a view in side elevation illustrating a modified form of perforating member; and

FIG. 8 is a fragmentary axial sectional view taken on line 88 of FIG. 7.

Referring to the drawing, FIGS. 1 to 4, inclusive, illusstrate one embodiment of the invention in the nature of a tribution system. The pipe may be of any selected diameter, such as a diameter of from two inches to six inches or more. Alternatively, the member 10 may constitute the wall of acontainer having steel of the ap proximate composition, thickness, and hardness of steel pipe.

A fitting, such as a branch pipe fitting, is secured to wall 10 by any suitable means and consists of a T having a branch or leg portion 12 communicating with a crossconduit, here shown as having a large diameter portion 14 with the inner end of which the leg 12 communicates, t

and a smaller portion 16 axially aligned with the portion 14. The T is preferably secured to the wall 10 at the end of the part 14 thereof as by means of the weld 18 circumferentially of the part 14 to efiect a seal between part 14 and the wall 10. The reduced fitting portion 16 is preferably screw-threaded internally and externally. The leg 12 of the T may be beveled at its end as shown to accommodate a welded circumferential sealed joint with the end of a branch pipe (not shown) to which the contents of the pipe or container, of which the wall 10 forms a part, are to be supplied. The portion 16 has internal threads extending full length thereof which are preferably comparatively fine or of slow lead and preferably of the type having sixteen to twenty-four threads per inch although it is possible to use even finer threads than twenty-four threads per inch.

An elongated perforating member has an elongated externally screw-threaded portion 20 at one end thereof which is screw-threaded in the conduit or fitting portion 16, and said end portion is preferably provided with hexagonal or other non-circular tool-receiving socket (not shown) in the end thereof to receive a tool for rotating the same. The perforating member has an elongated shank portion 22 of slightly less diameter than the diameter of the threaded part 20 from which projects a tapered coaxial portion 24. A cylindrical coaxial free end portion 26 projects from the small diameter end of a plane perpendicular to the axis of the perforating member. We prefer to provide said face with an angle from ten to fifteen degrees from a plane perpendicular to the axis of the member. The portion 26 of the perforating tool is tubular as defined by a bore 30 extending axially thereof and of a depth preferably greater than the thickness of the wall 10 to be perforated. The bore 30 is preferably of a diameter at least equal to the radius of part 26. 7

By way of illustration and without intent to be limiting, it has been found that the device functions satisfactorily when a part 26 of th-ree-eights inch diameter has a bore therein of seven thirty-seconds inches diameter, so that the wall thickness of the cylindrioal wall of part 26 is approximately five sixty-fourths of an inch. In the case of a perforating member whose part 26 has a diameter of one-half inch /2"), the

bore 30 thereof may be of a diameter of five-sixteenths of I an inch A and the wall thickness of the part 26 branch pipe fitting. The numeral 10 designates a steel pipe, such as pipe used in gas lines or mains in a gas dis- I three thirty-seconds ("7 of an inch. In the event the part 26 is five-eighths of an inch in diameter, the bore thereof may be seven sixteenths of an inch in diameter and the wall thickness of the part 26 may be three thirty-seconds of an inch In the use of the device after the T-fitting has been secured to the Wall 10 to be perforated, the perforating tool is advanced by rotation thereof, the rate of advance 1 being determined by the lead of the screw-threaded portion 20. When the perforating tool advances, the tip Patented July 4, 1961 I 3 portion 29 thereof spaced the greatest distance from the opposite end of the tool initially contacts the wall 10 and commences to displace the metal of the wall 10. As the advance of the tool continues, a cold flow of the metal of wall 10 is caused in an action somewhat similar to extrusion, causing a central core portion 32 to be forced into the bore 30 of the tool as an annular groove 34 is formed in wall 10 and is progressively deepened by the rotating advance of the perforating tool as determined by the lead of the screw-thread part 20 of the tool. This groove forming action continues through the major portion of the thickness of the wall 10. The extrusion action terminates before the perforation is completed, and thereafter the action is characterized by the requirement to exert greater torque to produce rotative advance of the perforating tool. The final perforating action of the tool may be likened to a swaging action and completes the perforation by forming a tapered or flared mouth 48 thereat.

' The operation of the tool produces a slug of the character illustrated in FIG. 5 characterized by the stem portion 32 extruded in the tube bore 30 and having a diameter slightly less than the diameter of the bore 30 to accommodate rotation therein. An enlarged diameter head portion 36 completes the slug, and the same is usually characterized by a comparatively rough surface 38 of frusto conical shape whose inner or small diameter end is usually substantially equal to the diameter of the portion 26 of the tool. The outer end of the slug is usually displaced to convex shape at its margin 40 and usually is characterized by a convex central end portion 42. The overall length of the slug is substantially greater than the wall thickness of the wall from which it is formed and said dimension results from the extrusion of the stem portion 32 as illustrated, for example, 1n FIG. 3.

Inasmuch as the leading edge 29 of the tool is eccentric thereof, rotation of the tool tends to cause the tip of the tool to become laterally displaced. We have found that such lateral deflection and displacement can be limited by forming a plurality of circumferentially spaced inwardly projecting lugs in the fitting portion 14 with their inner surfaces spaced from the axis of part 14 a distance slightly greater than the radius of the tool portion 22 which is located therein when the tip of the tool contacts the plate 10. This provides free clearance for rotation of the tool without binding as long as t he tool is free from lateral deflection and serves as pos1t1ve means to limit lateral deflection of the tool in use.

When a slug has been cut from the plate 10 it 1s completely freed therefrom, and the extruded stem 32 thereof holds the same in a position preventing hinging thereof at a part of one edge thereof as the final separation of the slug occurs. In other words, the fitting of the stem 32 in the bore 30 of the tool prevents tilting of the slug which might otherwise permit it to hinge or swing at a limited portion of its margin at a time when the remainder of the margin thereof was cut free from the wall 10. This complete separation of the slug from the wall 10 insures that the slug is free to fall to a position spaced from the opening 36 as it is disengaged from the tool incident to run out of the tool toward the position illustrated in FIG. 1. Thus it will be apparent that -as the head portion 36 of the slug engages the inner mouth of the perforation it is stopped in its axial movement while the axial withdrawing movement of the tool continues, thereby separating the stem 32 from its seating socket 30 in the tool, and, when this separation is completed, the loose fit of the free stem 32 in the bore 46 prevents the slug from maintaining its position in the opening 46, espeoially in cases where the axis of the bore 46 is substantially horizontal as shown, or in which th axi i tilted with the enlarged inner flared mouth portion 48 of the perforation positioned lowermost.

When the perforating tool has been run out to the position seen in FIG. 1, gas or other fluid may flow through the perforation 46 and the fitting portion 14 around the withdrawn perforating tool and into the leg or branch 12 of the fitting. The thread fit of the part of the tool in the part 16 of the fitting is substantially free from leakage but a complete seal against leakage can be provided by threading a sealing cap 44 upon the external screw-threads of the fitting portion 16. Thereafter, if it should become desirable to close the perforation 46, this can be done by removing the cap 44 and again advancing the perforating tool until such time as the tapered portion 24 thereof seats in the outer end of the perforation 46 and thus acts as a valve to close the port 46. It will also be understood that, if regulation of the rate of flow is desired, this can be accomplished by advancing the tool to a selected position adjacent the outer mouth of the aperture 46 and in such position as to restrict flow therethrough.

A modified construction of perforating tool is illustrated in FIGS. 7 and 8. In this construction the perforating tool has a threaded end portion 50, a substantially cylindrical slightly reduced shank portion 52, a further reduced shank portion 54, a frusto conical or tapered portion 56, and a cylindrical end portion 58. The end portion 58 is tubular as defined by an axial bore 60 open at its end and extendingfor a length greater than the thickness of the wall 10 to be perforated thereby, so as to define a comparatively thin rigid tube wall 62. The tip of the tool in this instance is defined by a pair of oblique flat end face 64 extending at an angle to each other so as to define a substantially V-shaped contour,

'as seen in FIG. 8, with the apex 66 of the V located in a line extending diametrically of the tool, and thus providing two diametrically opposed aligned radial tool edges '66 or apices for contacting the work, such as the wall 10. The angular displacement between the planes in which the faces 64 lie and the axis of the tool is preferably substantially equal. Faces 64 are preferably displaced from about ten degrees to twenty degrees or more from a plane perpendicular to the axis of the tool, so that the included angle between said planes of faces 64 is preferably from about 140 degrees to about 160 degrees.

This tool operates in the same manner described above and produces a slug similar to that illustrated in FIGS. 5

-. and 6 and characterized by an extruded stern portion 32,

an overall length greater than the thickness of the wall 10 from which it is removed, and an enlarged head portion 36 of roughened and substantially frusto conical circumferential outline and with a convex end 40 interrupted by a recessed center portion 42.

The perforating member in all embodiments will preferably be formed of a low carbon tool steel which has been hardened to maximum toughness without making it brittle. One such steel which is particularly well suited for use in making this perforating member is known as Allegheny Ludlum No. 609, of 60-75 carbon steel. It is also possible to use mild steel of the type used for products to be processed on screw machines after the same has been carburized and hardened.

A series of tests have been made to ascertain the torque required to operate a perforating tool of the double bevel type shown in FIGS. 7 and 8. Ten tests of devices using a perforating tool having a inch punch or leading end portion, with a one-quarter inch axial bore, wherein the angular displacement or included angle between the beveled faces 64 was deg., and the threaded portion 50 of the tool had twenty threads per inch, revealed that in perforating the 7 inch thick wall of a steel pipe six inches in diameter, the average torque required to perforate the pipe as registered on a torque wrench was seventy pounds. Further tests of the same perforating apparatus used on steel pipe of lesser diameter, such as a two-inch pipe, showed that the same perforator described above with a inch diameter tubular tip portion required an average of forty-five pounds pull on a torque wrench to perforate the wall 10. A series of tests wherein a punch having a one-half inch diameter tubular tip of the double beveled character illustrated in FIG. 7 with a V inch axial bore and a 7 inch wall thickness, with a perforator threaded portion 50 having a lead of twenty threads per inch, was used to perforate a 5 inch thick wall of a steel pipe six inches in diameter, required one hundred pounds pull on a torque wrench. Thus it will be apparent that the force required to operate the device renders it particularly well suited for manual operation by the use of a long-handled wrench, and the device is well suited for use in the field under usual service conditions.

While the preferred embodiments of the invention have been illustrated and described, it will be understood that changes in the construction may be made within the scope of the appended claims without departing from the spirit of the invention.

We claim:

1. In means for perforating a wall of a steel member of substantially uniform thickness, comprising a tube secured to said wall to extend substantially perpendicularly to said wall and having an internally threaded end portion spaced from said wall and an elongated perforating tool screw-threaded at one end thereof to mate with said tube threads and formed of a metal harder than said wall, said tool having a reduced diameter substantially cylindrical concentric perforating end portion having an oblique end face, the improvement comprising an axial concentric bore in said perforating end portion open at said end face and of a depth greater than the thickness of said wall, said end face being defined by two oblique planes intersecting diametrically of said end face and defining a pair of aligned wall-engaging edges.

2. In means for perforating a wall of a steel member of substantially uniform thickness, comprising a tube secured to said wall to extend substantially perpendicularly to said wall and having an internally threaded end portion spaced from said wall and an elongated perforating tool screw-threaded at one end thereof to mate with said tube threads and formed of a metal harder than said wall, said tool having a reduced diameter substantially cylindrical concentric perforating end portion having an oblique end face, the improvement comprising an axial concentric bore in said perforating end portion open at said end face and of a depth greater than the thickness of said wall, said end face having a V-shaped profile defining a pair of aligned radial wall-engaging edges.

3. In means for perforating a wall of a steel member of substantially uniform thickness, comprising a tube secured to said wall to extend substantially perpendicularly to said wall and having an internally threaded end portion spaced from said wall and an elongated perforating tool screw-threaded at one end thereof to mate with said tube threads and formed of a metal harder than said wall, said tool having a reduced diameter substantially cylindrical concentric perforating end portion having an oblique end face, the improvement comprising an axial concentric bore in said perforating end portion open at said end face and of a depth greater than the thickness of said wall, said end face having a V-shaped profile defined by two oblique planes intersecting diametrically of said end face and displaced between deg. and deg.

4. Means for perforating a wall of a steel member of substantially uniform thickness, comprising a tube internally screw-threaded at one end and secured at its opposite end to said wall in substantially perpendicular relation thereto, and an elongated perforating tool having a threaded end mating with said tube threads and formed of a metal harder than said wall, said tool having an integral concentric reduced diameter cylindrical tubular end portion, the free edge of said tubular portion lying in oblique intersecting planes to define Wall-engaging radial apices perpendicular to the axis of said end portion.

5. Means for perforating a wall of a steel member of substantially uniform thickness, comprising a tube internally screw-threaded at one end and secured at its opposite end to said wall in substantially perpendicular relation thereto, and an elongated perforating tool having a threaded end mating with said tube threads and formed of a metal harder than said wall, said tool having an integral concentric reduced diameter cylindrical tubular end portion, the free edge of said tubular portion lying in two oblique planes intersecting diametrically of said tubular portion to define aligned wall-engaging radial apices.

References Cited in the file of this patent UNITED STATES PATENTS Re. 24,199 McDonald Aug. 21, 1956 1,020,302 Metz Mar. 12, 1912 1,881,787 Mample et a1. Oct. 11, 1932 2,382,639 Kenard Aug. 14, 1945 2,606,615 Pevey et al. Aug. 12, 1952 2,950,637 Merrill et a1. Aug. 30, 1960 

